Method of combustion



Dec. 18, 1934.

J. F. o` STRATTON METHOD OF COMBUSTION Filed Jan. 51, 1929 /Lf 51 f'@wif/mw 0&7? 70,5??

Patented Dec. 18,1934

V UNiTED STATES Parlizrrrk OFFICE Y l l 1,984,441r l l' f METHoD orcoMUs'rroN John F. o. Stratton, Pelham Manor, N. Y.

Application January 31, 1929, Serial No. 336,524

3 Claims.

The present invention relates to a new and improved method of oxidizingfuel.

One of the primary objects of the invention resides in the provision ofa novel method of fur? nace combustion in Which a highly turbulentcondition is created and maintained.

Another object is to provide a new and improved method of combustion inwhich turbulence in the furnace is created by aV controllable agent,such as an air blast, which isindependent of the chemical composition ofthe fuel, variations in the temperature, and the volume of the productsof combustion leaving the furnace.

:Another important object of the present invention residesV in theprovision of a novel method 'of lfurnace, combustion in which thedifferent stages of combustion are carried out under proper conditionsand in which an adequate time ele ment is provided.

The present invention is particularly adapted for use in furnaces of thegeneral character disclosed in my Patent No. 1,640,158, in which crushedcoal is burned in suspension in an upwardly directed blast of air. Theblast of air enters the combustion chamber from a nozzle defined by aslot in the bottom, and the chamber is greater in height than themaximum blast. For convenience, this method will be termed as a methodof Vertical jet combustion.

- A further object of the invention resides in th provision of a novelmethod of vertical jet cornbustion in which preferably crushed coal isburned, and in which, regardless of the form of the coal used, the coalis introduced not directly into the top of the blast, thereby providinga substantial time element insuring complete combustion, and moreparticularly substantial combustion before the particles reach the topof the blast.

Still another object isto provide a method of verticalI jet combustionin which the different phases of combustion are carried outsuccessively'in` an'increasing'temperature gradient in a singlecombustion chamber and in which a substantial time element for thecompletion of eachI phase is provided. f

A more specific object resides in the provision oi a novel method ofvertical jet combustion in which a counteriiow is set upbetween theincoming and outgoing products, the outgoing products serving to preheatthe incoming products, and the latter serving to protect the walls ofthe combustion chamber from the intense heat of the outgoing products.

An important object of the invention resides in the provision of a novelmethod of vertical jet (Cl. 11G-28) combustion in which the air blast isdirected into a combustion chamber substantially larger in lateral.cross-section and height than the blast so as to constitute the blast acentral upwardly eX- panding core and to cause the blast to induce adownward flow in the core surrounding space at the side walls of thechamber, and in which the fuel is introduced through one` or' more ofthe side walls into the space of downward trend. The fuel in the courseof its downward rncvement is heat- 1 ed by radiation from theincandescent blast, and protects the sidewalls from excessivetemperatures, and then entersI they baseof the blast as coke. A longtortuous path, of increasing temperature gradient fork the combustibleparticles 1 and gases thus is provided.

Other objects and advantages will become apparent as the descriptionproceeds.Y

In the accompanying drawing, Fig. 1 is a vertical sectional view'diagra-rnmaticv in character and taken substantially along line 1-1 ofFigure 2 of a furnace adapted for carrying out a method of combustionembodying the features of my invention. I

Fig. 2 is a transverse sectional view taken substantially along line 2 2of Fig. 1.`

The vmethod may be carri-ed outlfin furnaces' or diiferentconstructions., of which the furnace shown in the drawing is thepreferredv form.

The furnace comprisesy a vertical combustion chamber 10v of suitableform. In the present instance, lthe chamber. 10 is rectangular inhorizontal cross-section, comprising side. walls l1, l2, 13 and 14. Thebottom of the chamber 10 is partially closed. by four inclined end walls15, 16, 17 and 18 converging downwardly from the side wallsrespectively. The wallsv l5 to 18 at their lower edges dene a relativelynarrow elongated opening 19 constituting the upper edge of a throat'.`20, and serve to direct coal and slag fall- 40 ing thereon toward thethroat.

Underlying the combustion chamber is a closed ash pit 21 which alsoserves as an air pressure chamber. Ashes may be removed from the pit21`through an opening 22 normally closed 45:

by a door 23.

Preferably-the throat is surrounded byan air chamber 24 which opensdownwardly into` the ash pit 21 and which is connected through a duct 25adapted to receive air under pressure 50 two sections 27 defining anarrow elongated in- 5 5 `terrnediatev slot 28 extending longitudinallyof the throat, and serving as a nozzle for directing a vertical blast ofair from the ash pit 21 into the combustion chamber 10. The sections 27are adjustable to permit adjustment of the width of the slot 28, andpreferably are movable as a unit transversely of the throat 20 so as toshift the region of the air blast, the operating means therefor beingmore fully disclosed in my said prior patent. l

The furnacemay be utilized as the heating means for a variety of heatabsorbing units, and for purposes of illustration is shown in connectionwith the boiler comprising suitable heating tubes 29 disposed in a uegas chamber 30 communicating with the top lof vthe combustion chamber10.

The cross-sectional area of the combustion chamber 10 is substantiallylarger than that of the air blast throughout most of its intense portionfrom theinlet. Hence, while there may be no sharp line of demarcation,and while the blast may shift withina limited range, the blastconstitutes a central core separated from the walls 11 to 14 by a coresurrounding space. The air blast creates a suction in the bottom of thechamber about the blast inlet, thus causing a V downward trend of gasesin the coresurrounding space.

While the invention is not limited to specific dimensions and angles, Ihave found that good results are obtained if the expansion of theeffective portion of the air blast is limited to approximately 18fromthe vertical. Preferably, the end'walls 15 and 17 are inclinedapproximately 52 to the horizontal. i As a result, the core surroundingspace expands approximately 20" along the walls and 17.

'Means is provided for introducing any suitable fuel, preferably crushedcoal, into the space of downward trend surrounding the central core.This 4means may be of any suitable form, and may be provided in any oneor more ofthe side walls 11 to 14, and in the present instancescomprises a `pair `of downwardly and inwardly inclined openings`31 ineach wall. The Vertical position of these openings may be differentfordifficult kinds 'of fuel, depending on the time element desired.

In operatiomthe strong central air blast trends upwardly and Dinduces adownward trend of gases inthe surrounding space along the side walls 11to 14.' `Crushed coal is introduced into the space of downward trend. Inthe course of .its downward movement, the coal is heated, by radiationfrom the. incandescent central core, through the distillation phase, thelight and volatile hydrocarbonsand other ingredients being extracted toform a light coke. The temperature in the outer zone is relatively low,and the downwardly moving products ,shield and protect the adjacentwalls of the chamber 10 from the intense heat of the core. l y

The coke and combustible gases from the outer zone enter the base of theblast, and are immediately erupted. The coke rst passes through theYreduction phase, i. e., is heated to the temperature of the blast toprepare it for oxidation. The reduction phase is completed before thefuel particles reach the top of the blast. The particles are completelyoxidized in the blast. The particles during the oxidation phase aremolten and hence relatively heavy, particularly when crushed coal asdistinguished from powdered coal is used. As they reach the top of theblast, they fall back and are again erupted. The molten ash particlesspecifically heavier descend to the bottom of the chamber 10, and passthrough the throat into the ash pit 21. i

The blast creates a Violent turbulence which prevents stratication andthe formation of relatively quiescent gas pockets, and which henceproduces a thorough intimate mixture of fuel and air. This turbulencebeing created by the blast, can be positively controlled by regulatingthe blast. Due to the counterflow of the incoming products and theblast, a long tortuous path for the combustible, and a substantial timeelement are provided. The phases of combustion are separated along anincreasing temperature gradient, although no sharp lines of demarcationmay exist. Raw unburned particles are not present at the outlet of thechamber 10, and the combustion is complete. Any particles of fuel andash present at the outlet are relatively heavy. As a result, noparticles of fuel, ash or impurities such as sulphur are carried over tothe heat absorbing surfaces.

Y I claim as my invention:

1. The method of combustion which comprises directing a blast of air ofcombustion upwardly into a combustion chamber in laterally spacedrelation to the sides of the chamber so as to induce a downward trend ofgases about the confines of the upward blast, and introducing crushedcoal into the zone of downward trend about said blast for ultimatesuspension and oxidation in said blast.

2. The method of combustion which consists in introducing an upwardblast of air in a combustion chamber spaced inwardly from the side wallsthereof so as to induce an insulating down draft along the side walls,directing said down draft inwardly toward the base of the blast, andintroducing comminuted fuel into said down draft for movement with saiddown draft toward the base of said blast whereby said fuel is heated andcombustion initiated by the heat from said central blast, and completingthe combustion of such fuel as it is moved upwardly after it hasencountered said blast.

3. The method of combustion which consists in introducing an upwardblast of air into a combusticn chamber, t-he blast being so regulated asto define a central core having diverging limits within an angle of 36and being spaced inwardly from the side walls of the chamber a minimumof 20 to induce an insulating down draft along the side walls, directingsaid down draft inwardly towardthe base of the blast, and introducingcomminuted fuel into said down draft for movement with said down drafttoward the base of said blast whereby said fuel is heated and combustioninitiated by the heat from said central blast, and completing thecombustion of such fuel as it is moved upwardly after it has encounteredsaid blast.

JOHN F, O. STRATTON.

